super duty fire clay brick

ItemMML-LDN-10MML-LDN-12MML-LDN-13MML-LDN-15Chemical AnalysisAl2O3 (%)≥50≥45≥45≥41Fe2O3 (%)≤1.0≤1.2≤1.5≤1.5Refractoriness ()≥1750≥1750≥1750≥1740Refractoriness under load of 0.2 MPa ()1530150014801470Reheat linear change1450 3H 00 2H (%)-0.2-0.2-0.2-0.2Apparent Porosity (%)8-1012≤13≤15Cold Crushing Strength (MPa)90857060Bulk Density (g/cm--3)+0.5+0.45+0.4+0.3A superduty fireclay refractory brick with at least 33 to 43 per cent by weight Al2 O3 and 1 to 3 per cent by weight alkali oxide for use as a large-format bottom block in a solder plating bath in furnaces for manufacturing flat glass according to the float technique has a compressive strength of 35 to 60 N/mm2 and a gas permeability of less than 4 nPm. The brick possesses an open porosity of approx. 20 to 25 per cent by volume, a gas permeability of less than 3 nPm, preferably 0.5 to 2 nPm, and a hydrogen diffusion of less than 150 mm H2 O, preferably 30 to 100 mm H2 O.